Fuel unit



Aug. 11, 1964 c. w. LANG ETAL FUEL UNIT Filed NOV. 25, 1962 175' 50m We# United States Patent() M 3,143,967 FUEL UNIT Charles W. Lang and Robert W. Erikson, Rockford, Ill., assignors to Sundstrand Corporation, a corporation of Illinois Filed Nov. 23, 1962, Ser. No. 239,621 8 Claims. (Cl. 10S-4) This invention relates to a fuel pump and more particularly to a valve construction particularly adapted for use in connection with oil burner pumps.

It is the general object of the present invention to produce a new and improved valve construction for oil burner pumps.

It is a more speciiic object of the invention to produce an oil burner shutoff valve provided with new and novel bypass means whereby purging of air from the oil burner system can be more efficiently and effectively accomplished.

It is a further object of the present invention to produce a valve construction particularly adaptable for use in connection with a two-stage oil burner pump, said valve being provided with bypass means enabling the employment of both stages to effect purging of air in the system.

Other and further objects of the invention will be readily apparent from the following description and the accompanying drawing. The drawing is a diagrammatic view of a fuel circuit for an oil burner including a valve designed in accordance with the present invention.

While this invention is susceptible of embodiment in many different forms, there is shown in the drawing and will herein be described in detail a speciiic embodiment of the invention, with the understanding that the present disclosure is to be considered as an exempliiication of the principles of the invention and is not intended to limit the invention to the embodiment illustrated. The scope of the invention will be pointed out in the appended claims.

As previously indicated, the valve of the present invention is particularly adaptable for use with oil burner pumps and has been shown as used in conjunction with a fuel pump of the general type shown in the Robert W. Erikson Patent No. 2,751,847.

The drawing shows a pump 10 having a casing 11 provided with a chamber therein providing a reservoir 12. An inlet 13 opens into the reservoir and connects with a source of oil such as a supply tank and the reservoir is provided with an outlet 14 whereby excess oil is returned to the supply tank.

For pumping oil, there is provided a first stage 15 which includes a shaft 16 driven -by a motor (not shown) on which is mounted a pinion gear 17 having external teeth meshing with the internal teeth of ring gear 18 with the space between the gears, where the teeth thereof are not Vin mesh, filled with a crescent-shaped member 19 in the usual manner. An inlet 24B leads from the reservoir to the rst stage and the discharge from the first stage is into a discharge line 21.

Rotation of the shaft 16 serves to draw oil from the supply tank into the reservoir 12 to keep the same filled to the level of the inlet 20. Oil above the inlet 20 is passed by the first-stage pump into the rst-stage discharge 21.

Also mounted on the shaft 16 is a second-stage pump 22 which has a pinion gear 24, a ring gear 25, and cres- .Tcent 26 constructed similarly to that previously described.

3,143,957 Patented Aug. 1l., 1964 ICE the ow of oil to the oil burner nozzle and for this purpose it is provided with a bore 31 in which is iixed a sleeve 32. A piston valve 33 is reciprocable within the sleeve 32 and is provided with a closed end 34 located in a space at one end of the bore defining a valve chamber 35. The closed end 34 of the piston valve controls the outlet 36' to the oil burner.

The space within the hollow piston valve denes a spring chamber 37 in which a compression spring 38 is located, the spring serving to urge the piston valve vtoward the closed position shown.

The outer surface of the piston valve at the closed end thereof is provided with bypass passages in the form of slots 40 extending axially from the valve chamber and constantly communicating with an annular groove 41 n formed in the exterior surface of the piston valve at a point spaced from the closed end thereof. Bypass ports in the form of bleed hole 42 extend through the annular groove and open into the spring chamber 37. The upper end of the spring chamber communicates by way of ports 43 to annular space 44 surrounding the sleeve 32, which space in turn communicates with the return line 45 connected in turn to the return line 14.

For bypassing excess oil, return ports 46 are provided in the sleeve at the position shown and open into an annular space 47 which in turn is in communication with the conduit 48 connected to the reservoir 12 previously described. A gauge port 5t) is normally closed by a plug and communicates as shown with the valve chamber 35.

In normal operation of the valve, assuming the system to be completely purged of air, the rst-stage pump 15 serves to draw oil from the supply to the reservoir 12, and maintains the same filled to the level indicated. Oil in the reservoir passes through the screen or strainer 23 and may enter the inlet 27 of the second-stage pump, which inlet is located well below the oil level and hence communicates only with air-free oil.

Pressure generated by the second stage pumping means is directed into the valve chamber 35 and when the pressure exceeds the compression spring, the valve is lifted off its seat thereby permitting oil discharged by the second-stage pump to be directed to the oil burner through the outlet 36. As an excess of oil is delivered by the second-stage pumping means during normal operation, the pressure thereof serves to move the piston valve 33 farther from its seat, thereby establishing communication between the valve chamber 35 and the ports 46 via the axial slots 40. Such excess oil enters the space 47 and is returned to the reservoir through the conduit 48.

When the oil burner system has not been purged of air, it is necessary to eifect such purging before the burner can be put into use. Where high lifts or long lines are involved, two-stage units such as shown in the aforementioned Erikson patent are generally used tov eifect initial purging of air. The irst stage can pump air since its discharge is unrestricted. The second stage, however, cannot be utilized since its discharge is directed back to the suction chamber via the bleed slot shown in said Erikson patent. Neither can lthe gauge port be opened to reduce purging time since such a bleed slot provides a connection between the gauge port and the strainer chamber.

With the valve of the present construction, however, the bleed slot has been elimianted and replaced by bleed orifice or opening 42 which communicates with the spring chamber 37 in turn communicating with the return. With this construction, the second stage assists the first stage during the initial purging by the amount of air which can pass through the orifice 42. The oritice 42 is sized so that in initial purging of the air, the orifice will pass most of the pumping capacity, but when oil is being pumped, only a small portion of the oil can pass through the orifice. Thus, there is an automatic reduction of inlet line velocity at the completion of the purging, reducing the time of purging and permitting the use of long inlet lines. Additionally, the gauge port 5G can be opened to further accelerate the purging of air.

The advantages of the present construction will now be apparent. In the first place, as just described, both stages l5 and 22 are utilized to purge air from the fuel system. When the fuel flow is established, excess fuel from the second stage is bypassed through the conduit 48 into the reservoir 12 and thus being returned reduces the velocity required in the inlet 13 and the line to which said inlet is connected. This permits the use of longer inlet lines by keeping the vacuum loss due to fluid friction to a minimum.

When purging with the gauge port open, the entire capacity of both stages draws fuel from the supply tank and thus much faster purging is effected.

Thus it can be seen that the present valve construction, while utilizing many of the features of the valve shown in the Erikson patent previously referred to, incorporates certain additional features and improvements which increase its efliciency and the resulting efficiency of the system with which it is associated.

We claim:

l. An oil burner pump having, in combination, a casing, a pumping means in the casing, a reservoir in the casing to which the inlet of the pumping means is connected, said reservoir having an inlet thereto and said casing having an outlet therefrom adapted to be connected to a source of oil, a cylindrical bore in the casing closed at one end to form a valve chamber, an inlet port opening to said chamber and connected to the outlet of the pumping means, an outlet port leading from said chamber, a cylindrical sleeve fixed in the bore, a hollow piston valve slidable in said sleeve and controlling the outlet port, said valve having a closed end and generally cylindrical side walls to define in said bore a spring chamber separated by the piston valve from the valve chamber and said valve being movable in response to the pressure in the valve chamber toward open position, a spring in the spring chamber and contacting the valve to bias the valve toward closed position, bypass means including a bypass port opening through the valve to the spring chamber at a point spaced from the closed end of the valve, a bypass passage opening at one end to the valve chamber and constantly communicating with said bypass port, a return passage connecting the spring chamber with the outlet from the casing, a return port opening into the sleeve at a point remote from the valve chamber, an annular groove in the piston spaced from the closed end thereof and adapted upon movement of the valve to establish communication between the bypass passage and the return port, and means connecting the return port to said reservoir.

2. An oil burner pump having, in combination, a casing, a pumping means in the casing, a reservoir in the casing to which the inlet of the pumping means is connected, said reservoir having an inlet thereto and said casing having an outlet therefrom adapted to be connected to a source of oil, a cylindrical bore in the casing closed at one end to form a valve chamber, an inlet port opening -to said chamber and connected to the outlet of the pumping means, an outlet port leading from said chamber, a cylindrical sleeve fixed in the bore, a hollow piston valve slidable in said sleeve and controlling the outlet port, said valve having a closed end and generally cylindrical side walls to deline in said bore a spring chamber separated by the piston valve from the valve chamber and said valve being movable in response to the pressure in the valve chamber toward open position, a spring in the spring chamber and contacting the valve to bias the valve toward closed position, bypass means including an annular groove in the outer surface of the piston valve spaced from the closed end thereof, a bypass port in said groove opening through the valve and into the spring chamber, a bypass slot on the outer surface of the piston valve opening at one end to the valve chamber and constantlyrcommunicating with said annular groove, a return passage connecting the spring chamber with said outlet from the casing, a return port opening into the sleeve at a point remote from the Valve chamber and positioned to be out of communication with the annular groove when the valve is in or near its `closed position, movement of said valve beyond the last mentioned position serving to move said annular groove into communication with said return port, and means connecting the return port to said reservoir.

3. An oil burner pumping apparatus comprising, in combination, a casing, a pump in the casing, a reservoir in the casing to which the inlet of the pump is connected, means providing an inlet to the reservoir adapted to be connected to a source of oil, means providing a valve chamber in the casing, an inlet port opening to said valve chamber and connected to the pump outlet, an outlet port leading from said valve chamber, a valve member movable in said valve chamber and controlling the outlet port and movable in response to pressure in the valve chamber to a position opening said outlet port, means normally biasing the valve member to a position closing said outlet port, means providing a constantly open bleed passage leading past the Valve member, a return port remote from said outlet port constantly communicating with said bleed passage and adapted to be connected with said source of oil, a by-pass port leading from said valve chamber, means on the Valve member adapted to communicate said inlet port with said bypass port upon movement of the valve member to open position thereby to by-pass` excess oil, and means connecting the by-pass port to -said reservoir, the arrangement being such that on dry starts the pump is effective to purge air through the bleed passage to the source and after oil is obtained in the reservoir some oil is constantly delivered through the bleed passage to facilitate rapid valve closing on shut down while the major portion of excess fluid is returned through the by-pass port to the reservoir.

4. A combination as defined in claim 3, including a gauge port leading to said valve chamber and constantly communicating with said inlet port, said gauge port being normally closed but openable to atmosphere on dry starts to expedite air purging without communicating the reservoir with atmosphere.

5. A combination as defined in claim 3, wherein said previously recited pump may be described as a second stage pump, and including a iirst stage pump in said casing having its inlet communicating with said reservoir and its outlet adapted to be connected to said source, so that on dry starts both pumps will be effective to purge air to said source.

6. A combination as defined in claim 3, wherein said previously recited pump may be described as a second stage pump having its inlet communicating with a lower portion of said reservoir for delivering substantially airfree oil to said outlet port during normal operation, and including a rst stage pump having its inlet communieating with an upper portion of said reservoir for creating suction to draw oil from said source to said reservoir and having its outlet communicating with said return port.

7. An oil burner pumping apparatus comprising, in combination, a casing, a first stage pump in the casing, a second stage pump in the casing, a reservoir in the casing to which the inlets of said pumps are connected, an inlet to said reservoir and an outlet from said casing adapted to be connected to a source of fuel oil, means providing a valve bore in the casing, an outlet port at one end of the valve bore adapted to be connected with a burner, a valve member slidable in the valve bore and having an end portion controlling said outlet port, means normally biasing the valve member to a position closing said outlet port, an inlet port leading to the valve bore adjacent said outlet port and communicating with the outlet from the second stage pump so that the pressure of oil delivered by the second stage pump is elective to move the valve member to a position opening said outlet port, means providing a constantly open bleed passage communicating opposite ends of the valve bore and opposite ends of the valve member to facilitate rapid valve closing on burner shut down, a return port com municating with said valve bore at the end thereof remote from said outlet port, a passage connecting said return port and said casing outlet, a by-pass port leading to said valve bore and communicating with said reservoir, means on the valve member adapted to communicate said bypass port With said inlet port upon valve opening movement for returning to the rservoir the oil pumped by the second stage pump in excess of the burner requirement, and means connecting the outlet from the rst stage pump to said return port.

8. A combination as defined in claim 7, including a gauge port leading to said valve bore adjacent said one end thereof in constant communication with said inlet port and adapted to be closed during normal operation and optionally closed or open during dry starts, the arrangement being such that during normal operation the first stage pump creates suction to draw oil into said reservoir and return any excess to the source and said second stage pump delivers air-free oil to the burner port with most of the excess returned to the rservoir, and during dry starts both pumps are eiective to purge air.

References Cited in the le of this patent UNITED STATES PATENTS 2,229,231 Weyenberg Ian. 2l, 1941 2,309,683 Wahlmark Feb. 2, 1943 :2,311,916 Wahlmark Feb. 23, 1943 2,625,108 Logan Jan. 13, 1953 2,657,632 Kiefer Nov. 3, 1953 2,751,847 Erikson June 26, 1956 2,763,336 Erikson Sept. 18, 1956 2,931,314 Erikson et a1. Apr. 5, 1960 

1. AN OIL BURNER PUMP HAVING, IN COMBINATION, A CASING, A PUMPING MEANS IN THE CASING, A RESERVOIR IN THE CASING TO WHICH THE INLET OF THE PUMPING MEANS IS CONNECTED, SAID RESERVOIR HAVING AN INLET THERETO AND SAID CASING HAVING AN OUTLET THEREFROM ADAPTED TO BE CONNECTED TO A SOURCE OF OIL, A CYLINDRICAL BORE IN THE CASING CLOSED AT ONE END TO FORM A VALVE CHAMBER, AN INLET PORT OPENING TO SAID CHAMBER AND CONNECTED TO THE OUTLET OF THE PUMPING MEANS, AN OUTLET PORT LEADING FROM SAID CHAMBER, A CYLINDRICAL SLEEVE FIXED IN THE BORE, A HOLLOW PISTON VALVE SLIDABLE IN SAID SLEEVE AND CONTROLLING THE OUTLET PORT, SAID VALVE HAVING A CLOSED END AND GENERALLY CYLINDRICAL SIDE WALLS TO DEFINE IN SAID BORE A SPRING CHAMBER SEPARATED BY THE PISTON VALVE FROM THE VALVE CHAMBER AND SAID VALVE BEING MOVABLE IN RESPONSE TO THE PRESSURE IN THE VALVE CHAMBER TOWARD OPEN POSITION, A SPRING IN THE SPRING CHAMBER AND CONTACTING THE VALVE TO BIAS THE VALVE TOWARD CLOSED POSITION, BYPASS MEANS INCLUDING A BYPASS PORT OPENING THROUGH THE VALVE TO THE SPRING CHAMBER AT A POINT SPACED FROM THE CLOSED END OF THE VALVE, A BYPASS PASSAGE OPENING AT ONE END TO THE VALVE CHAMBER AND CONSTANTLY COMMUNICATING WITH SAID BYPASS PORT, A RETURN PASSAGE CONNECTING THE SPRING CHAMBER WITH THE OUTLET FROM THE CASING, A RETURN PORT OPENING INTO THE SLEEVE AT A POINT REMOTE FROM THE VALVE CHAMBER, AN ANNULAR GROOVE IN THE PISTON SPACED FROM THE CLOSED END THEREOF AND ADAPTED UPON MOVEMENT OF THE VALVE TO ESTABLISH COMMUNICATION BETWEEN THE BYPASS PASSAGE AND THE RETURN PORT, AND MEANS CONNECTING THE RETURN PORT TO SAID RESERVOIR. 